I posted this on AssaultWeb during the ARFC outage and got a few interesting responses. With ARFC back on line, I thought I would ask the dedicated Black Rifle community for it's thoughts. The AW post is here:
www.assaultweb.net/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=2;t=004898We're working on a new wildcat for the AR-15 type rifles. Granted it would require different magazines (that are readily available right now in 10 round variety) and a modified lower, but bear with me.
With all the talk of the 223 Rem just not quite doing the job with short barrels (M4) or not quite reaching far enough where terrain allows/dictates (Afghanistan), we are building a new round.
NOTE: We are not trying to offer this as a competitor to the 6.8, but more as another option intended perhaps more for the competition shooter or the enthusiast. As you can read in the AW post, the 6.8 is hard to beat so we're not even trying.
Right now, the final decision is whether to go 223 or 6mm (243). The 223 variety would allow simple conversion of existing 223 uppers - just chase out the chamber with the new reamer and replace the bolt. The 6mm would open up a whole new arena of ballistics.
So here are the numbers we're looking at. These are all based on 55,000 psi (the SAAMI max for the 223 Rem) and a 24" barrel.
In 223 caliber
Speer 55 gr (M193) - 3,600 fps (223 Rem FL = 3250)
Speer 62 gr (M855) - 3,400 fps (223 Rem FL = 3100)
Sierra 77 gr SMK - 3,200 fps (223 Rem = ~2800 fps)
In 6mm caliber
Sierra 90 gr - 3,000-3,175 fps 243 Win =~3000 fps)
Sierra 107 gr - 2,800 - 2,970 fps **
(** these do NOT fit the mag, but have to be loaded through the ejection port. The 3rd Gen of this lower would allow that round to seat in the mag ...) (243 Win =~ 3100 fps)
My question to you:
1 - Should be bother with this, or just work on something else, with the 223 AI, Mk262 and 6.8x43 offering "good enough"
2 - If we should go ahead, do we go with the 223 or the 6 mm version?
3 - Should we try a different caliber or approach all together?
Thanks for your time and answers.